A power delivery network may provide power to a microelectronic component, such as a microprocessor. It may be the goal of the power delivery network to provide the microelectronic component sufficient power at a nearly constant voltage. In order to provide a nearly constant voltage, many individual capacitors may be implemented in the power delivery network to provide a low equivalent series inductance (ESL) for the network. The numerous individual capacitors may be replaced by a single array capacitor (or a few array capacitors) because an array capacitor may also provide a low ESL. However, a single array capacitor may not provide an adequate equivalent series resistance (ESR) for the network.
In general, a capacitor stores energy in an electric field between a pair of conductive electrodes (i.e., positive and negative or power and ground). An array capacitor has several of the two types of conductive electrodes, or metal planes, separated by an insulating material and interleaved in a stack such that the electrodes alternate by type. Conductive interconnections are provided to connect each electrode to the other electrodes of the same type. The conductive interconnections do not connect electrodes of opposite type. Terminals are also provided to facilitate connection of the array capacitor to external components.
FIGS. 1A and 1B illustrate top-down views of a prior art array capacitor. FIG. 1A illustrates an electrode layer 100 of a first type including voids 110 and connection sites 120. FIG. 1B illustrates an electrode layer 150 of a second type including voids 160 and connection sites 170.
In an array capacitor, multiple electrode layers 100, 150 are alternated in an aligned stack and separated by an insulating material. In the aligned stack, conductive interconnections (not shown) for electrodes 100 connect to a first electrode 100 at connection sites 120, extend through the corresponding voids 160 of an adjacent electrode 150, and connect to the next electrode 100 in the stack. In such a manner, all electrodes 100 are interconnected. Similarly, conductive interconnections (not shown) for electrodes 150 connect to a first electrode 150 at connection sites 170, extend through corresponding voids 110 of an adjacent electrode 100, and connect to the next electrode 150 in the stack. Terminals (not shown) are provided for each electrode type so the capacitor may be connected to external electrical components.